> The problem is that damn undecidability, which is like a minefield of rakes. It's undecidable for a compiler to tell if a program will do anything (e.g. halt)

> The problem is that damn undecidability, which is like a minefield of rakes. It's undecidable for a compiler to tell if a program will do anything (e.g. halt). It's undecidable for a compiler to tell if two programs are equivalent. It's undecidable for a compiler to tell if a program is minimal. Only for Turing complete languages, to be clear. Now, of course, most interesting problems cannot really be solved in sub-Turing languages, but it's still a fundamental point to consider.